Means and method for patterning a substrate with a mask

Abstract

A multilayer mask for patterning a platinum (or other) layer formed on a substrate. The multilayer mask includes a first dielectric layer formed on the platinum layer, a bottom resist layer formed over the first dielectric layer, a second dielectric layer formed on the bottom resist layer, and a top (structure) resist layer formed on the second dielectric layer. The second dielectric layer is patterned using the top resist layer, and serves to prevent photoresist rounding. The first dielectric layer prevents “micro-masking” by acting as an etch stop during subsequent patterning of the bottom resist layer, which is performed using dry etching techniques. The first dielectric layer is then wet etched to expose the platinum layer.

1 . A means for patterning a substrate with a mask, the mask having at least one layer with or made of a wet-patternable dielectric which is resistant to a dry etching,  
     characterized 
 in that the layer ( 1 ) with or made of the dielectric is arranged below a bottom resist ( 2 ) of a three-layer resist ( 2 ,  3 ,  4 ).  
 
   
   
       2 . The means as claimed in  claim 1 , characterized in that the dielectric has at least one proportion of SiO 2 , Si 3 N 4 , SiO x N y , Al 2 O 3  and/or TiO 2  or wholly comprises one of said substances.  
   
   
       3 . The means as claimed in  claim 1  or  2 , characterized in that the layer ( 1 ) with or made of the dielectric has a thickness of 30 to 50 nm.  
   
   
       4 . A method for patterning a substrate using a mask, at least one layer of the multilayer mask having or comprising a wet-patternable dielectric which is resistant to dry etching,  
     characterized 
 in that the layer ( 1 ) with or made of the dielectric is applied to the substrate ( 20 ) before the application of a bottom resist ( 2 ) layer of a three-layer resist ( 2 ,  3 ,  4 ).  
 
   
   
       5 . The method as claimed in  claim 4 , characterized in that, after the patterning of the bottom resist ( 2 ) by means of a dry etching method, in particular an RIE method, the layer ( 1 ) with or made of the dielectric is etched wet-chemically.  
   
   
       6 . The method as claimed in  claim 5 , characterized in that the wet-chemical etching of the layer ( 1 ) made of or with a dielectric is effected using phosphoric acid (H 2 PO 3 ), hydrofluoric acid (HF) or ammonium-buffered HF (HF/NH 4 F).  
   
   
       7 . The method as claimed in  claim 6 , characterized in that the phosphoric acid is diluted with water in the ratio 1:1 and has a temperature of 70° C.  
   
   
       8 . The method as claimed in at least one of  claims 4  to  7 , characterized in that the layer ( 1 ) made of or with a dielectric is used as an etching stop, in particular in an automated method.